Q: What are the prime factors of the number 31,400?

 A: 2, 5, 157

Why are those the prime factors of the number 31,400?

Prime factors are the prime numbers that can be multipled together to equal the original number. You find the factors by dividing by prime numbers. It is best shown by creating a Factor Tree.

Factor Tree for the number 31,400

31,400
Factor Arrows
215,700
Factor Arrows
27,850
Factor Arrows
23,925
Factor Arrows
5785
Factor Arrows
5157

The numbers in bold above are the prime factors. If there are multiples, you only count them one time. This leads us to our prime factors of:

2, 5, 157

We can check our work by multiplying all of the prime factors together: 2 x 2 x 2 x 5 x 5 x 157 = 31,400

This can also be written as 23 x 52 x 1571 = 31,400

If you would like to know more, or need additional explanation, please review our prime factorization explanation.


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